The invention relates to devices capable of providing adherence to organs of the body for purposes of medical diagnosis and treatment. More particularly, the invention relates to devices capable of adhering to, holding, moving, stabilizing or immobilizing an organ.
In many areas of surgical practice, it may be desirable to manipulate an internal organ without causing damage to the organ. In some circumstances, the surgeon may wish to turn, lift or otherwise reorient the organ so that surgery may be performed upon it. In other circumstances, the surgeon may simply want to move the organ out of the way. In still other cases, the surgeon may wish to hold the organ, or a portion of it, immobile so that it will not move during the surgical procedure. Unfortunately, many organs are slippery and are difficult to manipulate. Holding an organ with the hands may be undesirable because of the slipperiness of the organ, and because the hands may be bulky, becoming an obstacle to the surgeon. Moreover, the surgeon""s hands ordinarily will be necessary for the procedure to be performed. Holding an organ with an instrument may damage the organ, especially if the organ is unduly squeezed, pinched or stretched.
The heart is an organ that may be more effectively treated if it can be manipulated. Many forms of heart manipulation may be useful, including holding the heart, moving it within the chest and immobilizing regions of it. Some forms of heart disease, such as blockages of coronary vessels, may best be treated through procedures performed during open-heart surgery. During open-heart surgery, the patient is typically placed in the supine position. The surgeon performs a median sternotomy, incising and opening the patient""s chest. Thereafter, the surgeon may employ a rib-spreader to spread the rib cage apart, and may incise the pericardial sac to obtain access to the heart. For some forms of open-heart surgery, the patient is placed on cardiopulmonary bypass (CPB) and the patient""s heart is arrested. Stopping the patient""s heart is a frequently chosen procedure, as many coronary procedures are difficult to perform if the heart continues to beat. CPB entails trauma to the patient, with attendant side effects and risks.
Once the surgeon has access to the heart, it may be necessary to lift the heart from the chest or turn it to obtain access to a particular region of interest. Such manipulations are often difficult tasks. The heart is a slippery organ, and it is a challenging task to grip it with a gloved hand or an instrument without causing damage to the heart. Held improperly, the heart may suffer ischemia, hematoma or other trauma. Held insecurely, the heart may drop back into the chest, which may cause trauma to the heart and may interfere with the progress of the operation.
A coronary bypass operation, for example, may involve concerns as to immobilization and as to reorientation of the heart. Once the surgeon has obtained access to the heart, the affected coronary artery may not be accessible without turning or lifting of the heart. Furthermore, the procedure of grafting a new vessel is a delicate one, and contractions of the heart muscle multiply the difficulties in performing the procedure.
Similar concerns may arise in cases where the surgery is far less invasive. In a lateral thoracotomy, for example, the heart may be accessed through a smaller incision in the chest. Arresting of the heart may not be feasible. Yet it may be necessary or desirable for a surgeon to manipulate the heart, such as by moving it or by immobilizing a portion of it during the operation.
The present invention provides a device for providing adherence to an organ, allowing the organ to be manipulated or immobilized. It should be noted that any references to xe2x80x9cadhesionxe2x80x9d or related terms do not use the term as it is frequently used in medicine, namely to describe an abnormal union of an organ or part with some other part by formation of fibrous tissue. Rather, xe2x80x9cadhesionxe2x80x9d and related words refer to adherence, the process of one thing holding fast to another, without them becoming pathologically joined.
There are many circumstances where it may be beneficial to have the present invention provide adherence to an organ. A surgeon may have a need, for example, simply to lift a gall bladder out of the way to access another organ. A more complex environment in which the present invention may be used is that of open-heart surgery. In this context, a surgeon may employ several forms of the present invention during a single operation, depending upon the need and the application. By selecting the form of the present invention that suits the task at hand, the surgeon may reduce the risk of trauma to the patient and improve the effectiveness of the surgery. Because the device may have multiple uses within open heart surgery, application of the device to heart tissue will be described in detail herein, with the understanding that the device may have application to other areas of medical practice as well.
The device may include a seal member that allows it to adhere to slippery bodily tissue, such as the surface of a heart. The surgeon may lift the heart or reposition it by manipulating the device, with the seal member adhering to the surface of the heart. The device may also be applied to the heart in a form in which the coronary contractions near the site of adhesion are minimized, effectively stabilizing or immobilizing an area of the heart. Adherence of the device is temporary, not permanent. The device can be configured to apply easily to the tissue, adhere firmly, remain adhered as long as needed, minimize the risk of accidental release, and release easily when needed. Importantly, the device can be designed to minimize the risk of tissue trauma that may result from adherence and release.
Upon engagement of the seal member with the surface of the heart, the seal member defines a chamber. The seal member may further define a vacuum port in fluid communication with the chamber. The seal member can be made, in part, of a compliant material that will permit it to conform to the surface of the heart and that will further permit it to maintain contact while the heart is contracting. In some cases, adherence may be improved by application of the vacuum pressure from a pump by way of the vacuum port, where at least a portion of the seal member deforms and substantially forms a seal against the surface. In other cases, adherence may be improved by other mechanical or hydraulic devices.
In some embodiments, the seal member may define multiple cavities and multiple vacuum ports, each vacuum port in fluid communication with each cavity. Upon application of independent vacuum pressure to each vacuum port, at least a portion of the seal member deforms and substantially forms a seal against the surface, providing vacuum-assisted adhesion between the device and the heart. Employment of multiple chambers and multiple vacuum ports, with independent vacuum pressure applied to each port, can provide an additional measure of safety. Leakage in one of the sealed chambers will not affect the others, and adhesion may be maintained even if the seal on one chamber fails.
The adherence of the device can be aided by the use of particular materials to form the seal member. In particular, the chamber may be defined in part by a semi-rigid material, e.g., formed in a cup-like shape, that provides the device with structural integrity, and prevents the seal member from collapsing under vacuum pressure. The seal member also may include a skirt-like member, however, that is coupled to the chamber. The skirt-like member can be formed from a tacky, deformable material that promotes adhesion to the heart tissue at the point of contact. In some embodiments, the tacky, deformable material may take the form of a silicone gel that is molded, cast, deposited, or otherwise formed to produce the skirt-like member. With such a material, it may be possible to fix the seal member to the heart tissue even when no vacuum pressure is applied by a pump.
When a tacky, deformable material is used in combination with vacuum pressure, the device may adhere to the heart safely and securely, and may permit the surgeon to reorient the heart or to immobilize a region of it. The semi-rigid chamber portion imparts structural integrity to the seal member, while the tacky, deformable material forming the skirt-like member provides a seal interface with the heart tissue that is both adherent and adaptive to the contour of the heart. Moreover, as the skirt-like member deforms, it produces an increased surface area for contact with the heart tissue. The increased surface area provides a greater overall contact area for adherence, and distributes the coupling force of the vacuum pressure over a larger tissue area to reduce tissue trauma.
In general, materials suitable for forming the chamber may be too rigid, and may cause ischemia, hematoma or other trauma to the heart. The incorporation of a deformable, skirt-like member, in accordance with the present invention, provides a buffer between the more rigid chamber material and the heart tissue. Materials of the kind ordinarily used to form the chamber also provide little if any tackiness. By contrast, tacky materials ordinarily are not well suited for adherence in conjunction with a vacuum. A device in accordance with the present invention provides a two-part construction that exploits the advantages of both types of materials. In particular, the less deformable material forms a chamber that stands up to vacuum pressure, while the more deformable, tacky material forms a skirt-like member that provides an atraumatic yet robust seal interface with the heart tissue.
In one embodiment, the present invention provides an organ manipulation device comprising a seal member having a chamber with a wall and a skirt-like member that extends outward from the chamber wall for contact with a surface of an organ. The skirt-like member is substantially compliant and tacky, thereby promoting adhesion with the organ surface. The device may include a vacuum port in fluid communication with an interior of the chamber, and may further include a valve that regulates fluid flow through the vacuum port. The device may be of a variety of shapes and sizes.
In another embodiment, the present invention provides a method for manipulating a heart, the method comprising engaging a seal member with the apex of the heart to define a chamber, at least a portion of the seal member being compliant and adhesive to heart tissue, applying vacuum pressure to a vacuum port associated with the chamber such that a portion of the seal member deforms to substantially seal the chamber against leakage, and using the seal member as a gripping point for lifting and turning the heart. The method may further include pacing the heart by applying electrical voltage or current to the apex of the heart through electrodes incorporated within the seal member.
The present invention also provides an alternative method for manipulating a heart, the method comprising engaging a seal member with the apex of the heart to define a chamber, at least a portion of the seal member being compliant and adhesive to heart tissue, and the seal member including an aperture and a flexible airtight and watertight membrane, drawing the membrane toward the aperture such that a portion of the seal member deforms to substantially seal the chamber against leakage, and using the seal member as a gripping point for lifting and turning the heart. The membrane may be drawn mechanically or hydraulically.
In a further embodiment, the invention provides a method for immobilizing a region of the heart, the method comprising using a seal member to define a region of immobilization, engaging a seal member with the surface of the heart to define a cavity, at least a portion of the seal member being compliant and adhesive to heart tissue, and applying vacuum pressure to a vacuum port associated with the cavity such that a portion of the seal member deforms to substantially seal the cavity against leakage.
The details of one or more embodiments of the present invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the present invention will be apparent from the description and drawings, and from the claims.